//===----------------------------------------------------------------------===//
namespace {
+ class GVN;
+ struct AvailableValueInBlock {
+ /// BB - The basic block in question.
+ BasicBlock *BB;
+ enum ValType {
+ SimpleVal, // A simple offsetted value that is accessed.
+ LoadVal, // A value produced by a load.
+ MemIntrin // A memory intrinsic which is loaded from.
+ };
+
+ /// V - The value that is live out of the block.
+ PointerIntPair<Value *, 2, ValType> Val;
+
+ /// Offset - The byte offset in Val that is interesting for the load query.
+ unsigned Offset;
+
+ static AvailableValueInBlock get(BasicBlock *BB, Value *V,
+ unsigned Offset = 0) {
+ AvailableValueInBlock Res;
+ Res.BB = BB;
+ Res.Val.setPointer(V);
+ Res.Val.setInt(SimpleVal);
+ Res.Offset = Offset;
+ return Res;
+ }
+
+ static AvailableValueInBlock getMI(BasicBlock *BB, MemIntrinsic *MI,
+ unsigned Offset = 0) {
+ AvailableValueInBlock Res;
+ Res.BB = BB;
+ Res.Val.setPointer(MI);
+ Res.Val.setInt(MemIntrin);
+ Res.Offset = Offset;
+ return Res;
+ }
+
+ static AvailableValueInBlock getLoad(BasicBlock *BB, LoadInst *LI,
+ unsigned Offset = 0) {
+ AvailableValueInBlock Res;
+ Res.BB = BB;
+ Res.Val.setPointer(LI);
+ Res.Val.setInt(LoadVal);
+ Res.Offset = Offset;
+ return Res;
+ }
+
+ bool isSimpleValue() const { return Val.getInt() == SimpleVal; }
+ bool isCoercedLoadValue() const { return Val.getInt() == LoadVal; }
+ bool isMemIntrinValue() const { return Val.getInt() == MemIntrin; }
+
+ Value *getSimpleValue() const {
+ assert(isSimpleValue() && "Wrong accessor");
+ return Val.getPointer();
+ }
+
+ LoadInst *getCoercedLoadValue() const {
+ assert(isCoercedLoadValue() && "Wrong accessor");
+ return cast<LoadInst>(Val.getPointer());
+ }
+
+ MemIntrinsic *getMemIntrinValue() const {
+ assert(isMemIntrinValue() && "Wrong accessor");
+ return cast<MemIntrinsic>(Val.getPointer());
+ }
+
+ /// MaterializeAdjustedValue - Emit code into this block to adjust the value
+ /// defined here to the specified type. This handles various coercion cases.
+ Value *MaterializeAdjustedValue(Type *LoadTy, GVN &gvn) const;
+ };
class GVN : public FunctionPass {
bool NoLoads;
BumpPtrAllocator TableAllocator;
SmallVector<Instruction*, 8> InstrsToErase;
+
+ typedef SmallVector<NonLocalDepResult, 64> LoadDepVect;
+ typedef SmallVector<AvailableValueInBlock, 64> AvailValInBlkVect;
+ typedef SmallVector<BasicBlock*, 64> UnavailBlkVect;
+
public:
static char ID; // Pass identification, replacement for typeid
explicit GVN(bool noloads = false)
}
- // Helper fuctions
- // FIXME: eliminate or document these better
+ // Helper fuctions of redundant load elimination
bool processLoad(LoadInst *L);
- bool processInstruction(Instruction *I);
bool processNonLocalLoad(LoadInst *L);
+ void AnalyzeLoadAvailability(LoadInst *LI, LoadDepVect &Deps,
+ AvailValInBlkVect &ValuesPerBlock,
+ UnavailBlkVect &UnavailableBlocks);
+ bool PerformLoadPRE(LoadInst *LI, AvailValInBlkVect &ValuesPerBlock,
+ UnavailBlkVect &UnavailableBlocks);
+
+ // Other helper routines
+ bool processInstruction(Instruction *I);
bool processBlock(BasicBlock *BB);
void dump(DenseMap<uint32_t, Value*> &d);
bool iterateOnFunction(Function &F);
return ConstantFoldLoadFromConstPtr(Src, &TD);
}
-namespace {
-
-struct AvailableValueInBlock {
- /// BB - The basic block in question.
- BasicBlock *BB;
- enum ValType {
- SimpleVal, // A simple offsetted value that is accessed.
- LoadVal, // A value produced by a load.
- MemIntrin // A memory intrinsic which is loaded from.
- };
-
- /// V - The value that is live out of the block.
- PointerIntPair<Value *, 2, ValType> Val;
-
- /// Offset - The byte offset in Val that is interesting for the load query.
- unsigned Offset;
-
- static AvailableValueInBlock get(BasicBlock *BB, Value *V,
- unsigned Offset = 0) {
- AvailableValueInBlock Res;
- Res.BB = BB;
- Res.Val.setPointer(V);
- Res.Val.setInt(SimpleVal);
- Res.Offset = Offset;
- return Res;
- }
-
- static AvailableValueInBlock getMI(BasicBlock *BB, MemIntrinsic *MI,
- unsigned Offset = 0) {
- AvailableValueInBlock Res;
- Res.BB = BB;
- Res.Val.setPointer(MI);
- Res.Val.setInt(MemIntrin);
- Res.Offset = Offset;
- return Res;
- }
-
- static AvailableValueInBlock getLoad(BasicBlock *BB, LoadInst *LI,
- unsigned Offset = 0) {
- AvailableValueInBlock Res;
- Res.BB = BB;
- Res.Val.setPointer(LI);
- Res.Val.setInt(LoadVal);
- Res.Offset = Offset;
- return Res;
- }
-
- bool isSimpleValue() const { return Val.getInt() == SimpleVal; }
- bool isCoercedLoadValue() const { return Val.getInt() == LoadVal; }
- bool isMemIntrinValue() const { return Val.getInt() == MemIntrin; }
-
- Value *getSimpleValue() const {
- assert(isSimpleValue() && "Wrong accessor");
- return Val.getPointer();
- }
-
- LoadInst *getCoercedLoadValue() const {
- assert(isCoercedLoadValue() && "Wrong accessor");
- return cast<LoadInst>(Val.getPointer());
- }
-
- MemIntrinsic *getMemIntrinValue() const {
- assert(isMemIntrinValue() && "Wrong accessor");
- return cast<MemIntrinsic>(Val.getPointer());
- }
-
- /// MaterializeAdjustedValue - Emit code into this block to adjust the value
- /// defined here to the specified type. This handles various coercion cases.
- Value *MaterializeAdjustedValue(Type *LoadTy, GVN &gvn) const {
- Value *Res;
- if (isSimpleValue()) {
- Res = getSimpleValue();
- if (Res->getType() != LoadTy) {
- const DataLayout *TD = gvn.getDataLayout();
- assert(TD && "Need target data to handle type mismatch case");
- Res = GetStoreValueForLoad(Res, Offset, LoadTy, BB->getTerminator(),
- *TD);
-
- DEBUG(dbgs() << "GVN COERCED NONLOCAL VAL:\nOffset: " << Offset << " "
- << *getSimpleValue() << '\n'
- << *Res << '\n' << "\n\n\n");
- }
- } else if (isCoercedLoadValue()) {
- LoadInst *Load = getCoercedLoadValue();
- if (Load->getType() == LoadTy && Offset == 0) {
- Res = Load;
- } else {
- Res = GetLoadValueForLoad(Load, Offset, LoadTy, BB->getTerminator(),
- gvn);
-
- DEBUG(dbgs() << "GVN COERCED NONLOCAL LOAD:\nOffset: " << Offset << " "
- << *getCoercedLoadValue() << '\n'
- << *Res << '\n' << "\n\n\n");
- }
- } else {
- const DataLayout *TD = gvn.getDataLayout();
- assert(TD && "Need target data to handle type mismatch case");
- Res = GetMemInstValueForLoad(getMemIntrinValue(), Offset,
- LoadTy, BB->getTerminator(), *TD);
- DEBUG(dbgs() << "GVN COERCED NONLOCAL MEM INTRIN:\nOffset: " << Offset
- << " " << *getMemIntrinValue() << '\n'
- << *Res << '\n' << "\n\n\n");
- }
- return Res;
- }
-};
-
-} // end anonymous namespace
/// ConstructSSAForLoadSet - Given a set of loads specified by ValuesPerBlock,
/// construct SSA form, allowing us to eliminate LI. This returns the value
return V;
}
+Value *AvailableValueInBlock::MaterializeAdjustedValue(Type *LoadTy, GVN &gvn) const {
+ Value *Res;
+ if (isSimpleValue()) {
+ Res = getSimpleValue();
+ if (Res->getType() != LoadTy) {
+ const DataLayout *TD = gvn.getDataLayout();
+ assert(TD && "Need target data to handle type mismatch case");
+ Res = GetStoreValueForLoad(Res, Offset, LoadTy, BB->getTerminator(),
+ *TD);
+
+ DEBUG(dbgs() << "GVN COERCED NONLOCAL VAL:\nOffset: " << Offset << " "
+ << *getSimpleValue() << '\n'
+ << *Res << '\n' << "\n\n\n");
+ }
+ } else if (isCoercedLoadValue()) {
+ LoadInst *Load = getCoercedLoadValue();
+ if (Load->getType() == LoadTy && Offset == 0) {
+ Res = Load;
+ } else {
+ Res = GetLoadValueForLoad(Load, Offset, LoadTy, BB->getTerminator(),
+ gvn);
+
+ DEBUG(dbgs() << "GVN COERCED NONLOCAL LOAD:\nOffset: " << Offset << " "
+ << *getCoercedLoadValue() << '\n'
+ << *Res << '\n' << "\n\n\n");
+ }
+ } else {
+ const DataLayout *TD = gvn.getDataLayout();
+ assert(TD && "Need target data to handle type mismatch case");
+ Res = GetMemInstValueForLoad(getMemIntrinValue(), Offset,
+ LoadTy, BB->getTerminator(), *TD);
+ DEBUG(dbgs() << "GVN COERCED NONLOCAL MEM INTRIN:\nOffset: " << Offset
+ << " " << *getMemIntrinValue() << '\n'
+ << *Res << '\n' << "\n\n\n");
+ }
+ return Res;
+}
+
static bool isLifetimeStart(const Instruction *Inst) {
if (const IntrinsicInst* II = dyn_cast<IntrinsicInst>(Inst))
return II->getIntrinsicID() == Intrinsic::lifetime_start;
return false;
}
-/// processNonLocalLoad - Attempt to eliminate a load whose dependencies are
-/// non-local by performing PHI construction.
-bool GVN::processNonLocalLoad(LoadInst *LI) {
- // Find the non-local dependencies of the load.
- SmallVector<NonLocalDepResult, 64> Deps;
- AliasAnalysis::Location Loc = VN.getAliasAnalysis()->getLocation(LI);
- MD->getNonLocalPointerDependency(Loc, true, LI->getParent(), Deps);
- //DEBUG(dbgs() << "INVESTIGATING NONLOCAL LOAD: "
- // << Deps.size() << *LI << '\n');
-
- // If we had to process more than one hundred blocks to find the
- // dependencies, this load isn't worth worrying about. Optimizing
- // it will be too expensive.
- unsigned NumDeps = Deps.size();
- if (NumDeps > 100)
- return false;
-
- // If we had a phi translation failure, we'll have a single entry which is a
- // clobber in the current block. Reject this early.
- if (NumDeps == 1 &&
- !Deps[0].getResult().isDef() && !Deps[0].getResult().isClobber()) {
- DEBUG(
- dbgs() << "GVN: non-local load ";
- WriteAsOperand(dbgs(), LI);
- dbgs() << " has unknown dependencies\n";
- );
- return false;
- }
+void GVN::AnalyzeLoadAvailability(LoadInst *LI, LoadDepVect &Deps,
+ AvailValInBlkVect &ValuesPerBlock,
+ UnavailBlkVect &UnavailableBlocks) {
// Filter out useless results (non-locals, etc). Keep track of the blocks
// where we have a value available in repl, also keep track of whether we see
// dependencies that produce an unknown value for the load (such as a call
// that could potentially clobber the load).
- SmallVector<AvailableValueInBlock, 64> ValuesPerBlock;
- SmallVector<BasicBlock*, 64> UnavailableBlocks;
-
+ unsigned NumDeps = Deps.size();
for (unsigned i = 0, e = NumDeps; i != e; ++i) {
BasicBlock *DepBB = Deps[i].getBB();
MemDepResult DepInfo = Deps[i].getResult();
}
UnavailableBlocks.push_back(DepBB);
- continue;
}
+}
- // If we have no predecessors that produce a known value for this load, exit
- // early.
- if (ValuesPerBlock.empty()) return false;
-
- // If all of the instructions we depend on produce a known value for this
- // load, then it is fully redundant and we can use PHI insertion to compute
- // its value. Insert PHIs and remove the fully redundant value now.
- if (UnavailableBlocks.empty()) {
- DEBUG(dbgs() << "GVN REMOVING NONLOCAL LOAD: " << *LI << '\n');
-
- // Perform PHI construction.
- Value *V = ConstructSSAForLoadSet(LI, ValuesPerBlock, *this);
- LI->replaceAllUsesWith(V);
-
- if (isa<PHINode>(V))
- V->takeName(LI);
- if (V->getType()->getScalarType()->isPointerTy())
- MD->invalidateCachedPointerInfo(V);
- markInstructionForDeletion(LI);
- ++NumGVNLoad;
- return true;
- }
-
- if (!EnablePRE || !EnableLoadPRE)
- return false;
-
+bool GVN::PerformLoadPRE(LoadInst *LI, AvailValInBlkVect &ValuesPerBlock,
+ UnavailBlkVect &UnavailableBlocks) {
// Okay, we have *some* definitions of the value. This means that the value
// is available in some of our (transitive) predecessors. Lets think about
// doing PRE of this load. This will involve inserting a new load into the
return true;
}
+/// processNonLocalLoad - Attempt to eliminate a load whose dependencies are
+/// non-local by performing PHI construction.
+bool GVN::processNonLocalLoad(LoadInst *LI) {
+ // Step 1: Find the non-local dependencies of the load.
+ LoadDepVect Deps;
+ AliasAnalysis::Location Loc = VN.getAliasAnalysis()->getLocation(LI);
+ MD->getNonLocalPointerDependency(Loc, true, LI->getParent(), Deps);
+
+ // If we had to process more than one hundred blocks to find the
+ // dependencies, this load isn't worth worrying about. Optimizing
+ // it will be too expensive.
+ unsigned NumDeps = Deps.size();
+ if (NumDeps > 100)
+ return false;
+
+ // If we had a phi translation failure, we'll have a single entry which is a
+ // clobber in the current block. Reject this early.
+ if (NumDeps == 1 &&
+ !Deps[0].getResult().isDef() && !Deps[0].getResult().isClobber()) {
+ DEBUG(
+ dbgs() << "GVN: non-local load ";
+ WriteAsOperand(dbgs(), LI);
+ dbgs() << " has unknown dependencies\n";
+ );
+ return false;
+ }
+
+ // Step 2: Analyze the availability of the load
+ AvailValInBlkVect ValuesPerBlock;
+ UnavailBlkVect UnavailableBlocks;
+ AnalyzeLoadAvailability(LI, Deps, ValuesPerBlock, UnavailableBlocks);
+
+ // If we have no predecessors that produce a known value for this load, exit
+ // early.
+ if (ValuesPerBlock.empty())
+ return false;
+
+ // Step 3: Eliminate fully redundancy.
+ //
+ // If all of the instructions we depend on produce a known value for this
+ // load, then it is fully redundant and we can use PHI insertion to compute
+ // its value. Insert PHIs and remove the fully redundant value now.
+ if (UnavailableBlocks.empty()) {
+ DEBUG(dbgs() << "GVN REMOVING NONLOCAL LOAD: " << *LI << '\n');
+
+ // Perform PHI construction.
+ Value *V = ConstructSSAForLoadSet(LI, ValuesPerBlock, *this);
+ LI->replaceAllUsesWith(V);
+
+ if (isa<PHINode>(V))
+ V->takeName(LI);
+ if (V->getType()->getScalarType()->isPointerTy())
+ MD->invalidateCachedPointerInfo(V);
+ markInstructionForDeletion(LI);
+ ++NumGVNLoad;
+ return true;
+ }
+
+ // Step 4: Eliminate partial redundancy.
+ if (!EnablePRE || !EnableLoadPRE)
+ return false;
+
+ return PerformLoadPRE(LI, ValuesPerBlock, UnavailableBlocks);
+}
+
+
static void patchReplacementInstruction(Instruction *I, Value *Repl) {
// Patch the replacement so that it is not more restrictive than the value
// being replaced.
projects / oota-llvm.git / commitdiff